Do you mean you make your media, add serum then filter??
We make media, filter and then add serum to the bottles as we use it.........

Is the particulate matter from the serum? WE have NCS tends to have more particulate matter than FCS, and this varies depending on supplier. You could try pelleting it out of your serum before you add it to the media??

But no, I have never filtered my media with serum in (although I did work for a lab that insisted that all media+serum was always filtered, using a 0.2 micron filter).

Do you mean you make your media, add serum then filter??We make media, filter and then add serum to the bottles as we use it.........

Is the particulate matter from the serum? WE have NCS tends to have more particulate matter than FCS, and this varies depending on supplier. You could try pelleting it out of your serum before you add it to the media??

But no, I have never filtered my media with serum in (although I did work for a lab that insisted that all media+serum was always filtered, using a 0.2 micron filter).

Yeah my last lab did that too, never was really sure why. We used cosmic calf serum which had a lot of particulate matter but it was triple filtered by the manufacturer. Just seemed redudant and was wondering if that was common practice or not.

Just a general question. Do you folks typically filter out particulate matter from your media (with serum) prior to use? And if so do you use .25 or .45 micron filters?

Thanks!

There should be no particulates in the synthetic liquid media. Foetal Calf/Bovine serum is already filtered by the manufacturers through a 0.1uM filter. However, you do get protein preciptates coming from the serum, which do not need to be filtered. Every extra step in manipulating media and serum INCREASES the chances of YOU introducing contamination. There can also be precipitates from Glutamine that has not been warmed up properly before addition.

As a general note for Tissue Culture....never use a 0.45uM Filter.....IT IS NOT A STERILISING FILTER.

The other thing to note is that using filters...i.e. 500ml and 1L filters is an extra expense that is not required.